The present invention relates generally to improvements in electrical coupling devices and it relates more particularly to an improved wire coupling device for the grounding of a conductor housing metal conduit.
In conventional electrical distribution systems in dwellings and in commercial and industrial buildings, it is a common practice to enclose the electrical power lines in metal conduit which is for many reasons, generally grounded. The grounding of the electrical conduits is usually effected by connecting a grounded, heavy cable to the various conduits of the installation. By reason of the heavy current which must frequently be transferred to the grounding cable due to surges and other circumstances it is necessary that reliable and low resistance electrical coupling be effected between the grounding cable and the associated electrical conduits. To this end numerous conduit grounding cable coupling devices have been employed and proposed but these have heretofore possessed numerous drawbacks. A conduit grounding wire coupling device which is highly satisfactory up to a point is disclosed in U.S. Pat. No. 3,967,872 granted July 6, 1976 to T. Mooney and R. A. Bauer. However, while the aforesaid patented coupling device is adjustable to interconnect differently oriented conduit and grounding cable, it possesses an important disadvantage. Should there be any deviation in the orientation of the grounding cable or conduit or should there be any angular stress or torque between the grounding cable and the conduit there could result a loosening of the coupling device with the consequent increase in the electrical resistance thereof, particularly in the causing and presence of corrosion at coupling interfaces. Accordingly, the conduit grounding wire coupling devices heretofore available or proposed leave much to be desired.